[PATCH net] selftests: drv-net: tso: don't touch dangerous feature bits

[Jakub Kicinski <kuba@kernel.org>]

query_nic_features() detects which offloads depend on tx-gso-partial
by enabling everything, turning tx-gso-partial off, and seeing which
active features drop out. Enabling all hw features is dangerous:
we may end up enabling rx-fcs and loopback for example. For the
ice driver we end up getting into problems with feature dependencies
so the cleanup isn't successful either, and the test exits with
rx-fcs and loopback enabled.

Scope the feature probing just to segmentation bits.

Fixes: 266b835e5e84 ("selftests: drv-net: tso: enable test cases based on hw_features")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: shuah@kernel.org
CC: daniel.zahka@gmail.com
CC: linux-kselftest@vger.kernel.org
---
 tools/testing/selftests/drivers/net/hw/tso.py | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/tso.py b/tools/testing/selftests/drivers/net/hw/tso.py
index 1b789fea8929..802bb4868046 100755
--- a/tools/testing/selftests/drivers/net/hw/tso.py
+++ b/tools/testing/selftests/drivers/net/hw/tso.py
@@ -187,28 +187,24 @@ from lib.py import bkg, cmd, defer, ethtool, ip, rand_port, wait_port_listen
         cfg.wanted_features.add(f["name"])
 
     cfg.hw_features = set()
-    hw_all_features_cmd = ""
     for f in features["hw"]["bits"]["bit"]:
         if f.get("value", False):
-            feature = f["name"]
-            cfg.hw_features.add(feature)
-            hw_all_features_cmd += f" {feature} on"
-    try:
-        ethtool(f"-K {cfg.ifname} {hw_all_features_cmd}")
-    except Exception as e:
-        ksft_pr(f"WARNING: failure enabling all hw features: {e}")
-        ksft_pr("partial gso feature detection may be impacted")
+            cfg.hw_features.add(f["name"])
 
     # Check which features are supported via GSO partial
     cfg.partial_features = set()
     if 'tx-gso-partial' in cfg.hw_features:
+        seg_features = {f for f in cfg.hw_features if "segmentation" in f}
+        ethtool(f"-K {cfg.ifname} " +
+                " ".join(f"{f} on" for f in seg_features))
+
         ethtool(f"-K {cfg.ifname} tx-gso-partial off")
 
         no_partial = set()
         features = cfg.ethnl.features_get({"header": {"dev-index": cfg.ifindex}})
         for f in features["active"]["bits"]["bit"]:
             no_partial.add(f["name"])
-        cfg.partial_features = cfg.hw_features - no_partial
+        cfg.partial_features = seg_features - no_partial
         ethtool(f"-K {cfg.ifname} tx-gso-partial on")
 
     restore_wanted_features(cfg)
-- 
2.54.0